Review of Formula 311 SRI

The hull is made of fibreglass while the deck is made of hand laid fibreglass. Generally, a hull made of fibreglass requires only a minimum of maintenance during the sailing season. And outside the sailing season, just bottom cleaning and perhaps anti-fouling painting once a year - a few hours of work, that's all.

Both the hull and the deck is a sandwich construction which improves the indoor climate. Especially when the water is colder than the air in the cabin, then the double hull insulates against cold water and reduce the condense water in the cabin.

The interior is like most other boats made of teak. Teak has the advantage of being naturally very oily and therefore water-repellent, which is suitable on boats.
The boat is equipped with one cabin, 4-5 berths, a galley, 53.0 liter fresh water capacity and toilet facility.

Unknown keel type

The boat can enter even shallow marinas as the draft is just about 0.88 - 0.98 meter (2.89 - 3.19 ft) dependent on the load. See immersion rate below.

Formula 311 SRI may be equipped with dual inboard MerCruiser engines at 660 hp (491 kW). The speed is 67.0 knots.

The transmission is a Z-drive aka sterndrive.

The fuel tank, which is made of stainless steel, has a capacity of 572.0 liters (151 US gallons, 125 imperial gallons).

The immersion rate is defined as the weight required to sink the boat a certain level. The immersion rate for Formula 311 SRI is about 154 kg/cm, alternatively 865 lbs/inch.
Meaning: if you load 154 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 865 lbs cargo on the boat it will sink 1 inch.

What is L/B (Length Beam Ratio)?

The l/b ratio for Formula 311 SRI is 3.87.

Compared with other similar motor boats it is slimmer than 100% of all other designs. It seems that the designer has chosen a significantly more speedy hull design. This type of design is also referred to as 'needle'.

In Denmark, you are required to have achieved a 'powerboat driving license' in order to sail a powerboat.
In this context a boat is considered a powerboat if:

According to this definition this boat is categorized as a Powerboat.

This section is reserved boat owner's modifications, improvements, etc. Here you might find (or contribute with) inspiration for your boat.

Do you have changes/improvements you would like to share? Upload a photo and describe what you have done.

We are always looking for new photos. If you can contribute with photos for Formula 311 SRI it would be a great help.

If you have any comments to the review, improvement suggestions, or the like, feel free to contact us. Criticism helps us to improve.

[Ref 1]: ISO 8666 Small craft — Principal data.
[Ref 3]: ISO 12215-5 Small craft — Hull construction and scantlings.